Genetically Modified Foods, nothing to fear

Genetically modified crops (GMs or GMOs for genetically modified organisms) have existed for thousands of years, but now that we know how to splice genes in the laboratory, there is concern over food safety.  Much of that concern is unwarranted.  Nevertheless, there are campaigns to require product labeling when some foodstuffs contain GMOs. (See a story about such a campaign in Tucson here.) The food industry is generally against that requirement for two reasons: 1) it implies that the produce is somehow inferior to non-modified foods, and 2) costs; it could require companies to have separate processing lines for GMO and non-GMO foods.

The American Association for the Advancement of Science has a statement on GMOs and labeling which begins:

“There are several current efforts to require labeling of foods containing products derived from genetically modified crop plants, commonly known as GM crops or GMOs. These efforts are not driven by evidence that GM foods are actually dangerous. Indeed, the science is quite clear: crop improvement by the modern molecular techniques of biotechnology is safe. Rather, these initiatives are driven by a variety of factors, ranging from the persistent perception that such foods are somehow “unnatural” and potentially dangerous to the desire to gain competitive advantage by legislating attachment of a label meant to alarm. Another misconception used as a rationale for labeling is that GM crops are untested.”

See full statement here.

Humans have been genetically modifying food crops for a long time.  Ever hear of teosinte?  It is a grass that grows in Mexico and Central America.  Many thousands of years ago, farmers began selecting the seeds from certain individual teosinte plants that favored larger seeds or kernels and planted these larger seeds to encourage the trait.  This process is known as selective breeding or artificial selection. Eventually the plant became known as maize (corn).  The maize or corn cob looks nothing like the original plant but, according to the University of Utah, “at the DNA level, the two are surprisingly alike. They have the same number of chromosomes and a remarkably similar arrangement of genes. In fact, teosinte can cross-breed with modern maize varieties to form maize-teosinte hybrids that can go on to reproduce naturally.”

Beginning in the 1950s, Norman Borlaug, so-called father of the Green Revolution, took selective breeding to new heights.  His work helped save millions of lives.  An article in Forbes Magazine recounts the story:

“First, he and his colleagues laboriously crossbred thousands of wheat varieties from around the world to produce some new ones with resistance to rust, a destructive plant pest; this raised yields 20% to 40%.

“Second, he crafted so-called dwarf wheat varieties, which were smaller than the old shoulder-high varieties that bent in the wind and touched the ground (thereby becoming unharvestable); the new waist or knee-high dwarfs stayed erect and held up huge loads of grain.  The yields were boosted even further.

“Third, he devised an ingenious technique called “shuttle breeding”– growing two successive plantings each year, instead of the usual one, in different regions of Mexico.  The availability of two test generations of wheat each year cut by half the years required for breeding new varieties.  Moreover, because the two regions possessed distinctly different climatic conditions, the resulting new early-maturing, rust-resistant varieties were broadly adapted to many latitudes, altitudes and soil types.  This wide adaptability, which flew in the face of agricultural orthodoxy, proved invaluable, and Mexican wheat yields skyrocketed.”

As a result, Mexico became an exporter of wheat and India and Pakistan doubled their production.

Borlaug’s work also led to the development of high-yield rice, including vitamin-A-rich “golden rice” in Asia.

Advances in molecular biology allow gene splicing to produce GMOs faster than the older method of selective breeding.  Is this unnatural?  I suppose that strictly speaking it is, but it just continues a process that we have been using for thousands of years.  Modern gene splicing makes it easier to create crops with desirable characteristics and also easier to make sure undesirable traits are prevented or eliminated.

GMOs have been a controversial topic in the European Union.  Last year, however, the European Commission’s Chief Scientific Advisor said “Genetically modified organisms (GMOs) are no riskier than their conventionally farmed equivalents…There is no substantiated case of any adverse impact on human health, animal health or environmental health, so that’s pretty robust evidence, and I would be confident in saying that there is no more risk in eating GMO food than eating conventionally farmed food.”

Professor Alan McHughen, a plant molecular geneticist at UC Riverside wrote a book called “Pandora’s Picnic Basket: The Potential and Hazards of Genetically Modified Foods” in which he reviews the fears and facts surrounding GMOs.. McHughen is generally in favor of GMOs.  In a recent article he claims:

“GMO technologies have been around since the early 1970s and have given us many useful products, from human insulin to safer crops grown with fewer pesticides. Moreover, in over 30 years of experience, according to authoritative sources such as the U.S. National Academies and the American Medical Association, there is not one documented case of harm to humans, animals or the environment from GM products.”

McHughen does note that  “Recently, French scientist Gilles-Éric Séralini and his team published a peer-reviewed paper that claimed harm to test animals after they were fed GM corn for two years.”

Andrew Revkin of the New York Times writes of that study here.  The study claimed to find big impacts on longevity and cancer rates in rats fed Roundup-ready corn.  Revkin notes some red-flags in the study: “One issue is that, while the experiments ran for two years, far longer than most rat studies of food safety, the chosen rat breed commonly develops tumors after two years. Combined with small sample size (the different test groups had 20 animals each), this has led even some advocates for GMO labeling to question the results….Another red flag was that tumor rates didn’t increase in line with the dose of GMOs fed to animals, as scientists would expect to see if the genetically engineered corn were to blame…”

A study reported in Food and Chemical Toxicology, April, 2012, examined 12 long-term projects and 12 multi-generational studies of the effects of diets containing GM maize, potato, soybean, rice, or triticale (a hybrid of wheat and rye) on animal health.  ” Results from all the 24 studies do not suggest any health hazards and, in general, there were no statistically significant differences within parameters observed.”

One oft cited concern is allergic reaction to food.  Gene modification involves substituting or adding a protein, and almost any protein can be an allergen.  If you do an internet search of “GMO” and “allergies” you will find thousands of sites expressing concern but almost none providing any clinical evidence of GMO-caused allergies.  When American-grown Starlink corn was first introduced into the UK, many people claimed asthma symptoms worsened.  The CDC investigated but could not find a link.  GMO soybeans have also been accused of causing allergies.  A Korean clinical study found no difference in reactions to GMO and non-GMO soybeans.  Ironically, I saw that there are some attempts to reduce food allergies, such as to peanuts, through genetic modification. By law, if a new protein trait has been added, the protein must be shown to be neither toxic nor allergenic.

As far as I can tell, there are no significant health safety issues associated with GMO foods.  Calls for labeling such as the one reportedrecently in the Arizona Daily Star seem to be based on ignorance and fear rather than evidence.  If, however, there is some real proof that certain GMO foods cause adverse effects (like peanuts allergies), then such products should be labeled. We have been using GMO foods for a long time and, so far, no such danger has been identified.

For more information see an article by molecular biologist Michael Eisen “How Bt Corn And Roundup Ready Soy Work – And Why They Should Not Scare You.”  He writes: “Approximately 90% of soybeans, maize, cotton and sugar beets grown in the US are have been genetically modified to produce a protein that kills common insect pests or to make them highly tolerant of an herbicide used to control weeds, or in some cases both. To make a rational judgment about whether these specific GMOs are good or bad, it’s important to understand exactly what they are and how they work.”  He also notes that use of GMOs has greatly reduced the need for pesticides. See the rest of his article here.

Please take note: This post is about food safety and does not address the separate issue of possible cross-pollination from GMO crops, an issue of great economic concern to organic farmers.  However, I will mention that there are methods to minimize or prevent cross-pollination as discussed by the University of Minnesota here and the University of Arizona here. Organic farmers can also use GMO-resistant strains. For instance, a new lineage of organic corn hybrids, known as PuraMaize®, seek to end the battle of GMO corn contamination. Using a natural gene blocking system, these organic hybrids are able to prevent fertilization of foreign GMO and colored corn varieties.